The general purpose of this research is to develop an electrical stimulation system for preventing the formation of peritendinous adhesions during the rehabilitation period after tendon repair surgery in the hand. Digital tendon lacerations are common, occurring in 35% of open-wound finger injuries. After surgical repair of a severed tendon, scar tissue often develops and binds the healing tendon to adjacent tissues, resulting in a stiff digit with limited mobility and functionality. Motion exercise applied to the injured digit after tendon repair has been shown effective in improving tendon excursion and strength. However, with the conventional passive motion protocols, tendon gliding within the sheath is never ensured; the motion is not precisely controlled; and the success of the rehabilitation is highly dependent upon patient compliance. We propose to use percutaneous intramuscular electrical stimulation to actively move the injured finger with precise control, ensuring tendon glide and requiring no patient assistance. A preliminary clinical test will be conducted to establish surgical procedures, to evaluate the exercise protocol, and to assess user acceptance. The feasibility of the technical approach will be evaluated based on the capability of intramuscular stimulation to induce smooth and repeatable digital motions and on the initial medical outcomes. PROPOSED COMMERCIAL APPLICATIONS: This stimulation system can be used in the rehabilitation of the 10,000 cases of digital tendon lacerations that occur in the U.S. every year. By increasing the success rate of tendon repair surgery, costly follow-up medical interventions will be less frequent. Use of the stimulator could also decrease the service time required from therapists, thereby reducing medical care costs.